int Buffer::pushBytes(const uint8_t* bytes, int cnt)
{
if (writeAvailable() < cnt)
cnt = writeAvailable();
memcpy(_tail, bytes, cnt);
_tail += cnt;
return cnt;
}
std::vector<iovec>
Buffer::writeBuffers(size_t length)
{
if (length == (size_t)~0)
length = writeAvailable();
reserve(length);
std::vector<iovec> result;
result.reserve(m_segments.size());
size_t remaining = length;
std::list<Segment>::iterator it = m_writeIt;
while (remaining > 0) {
Segment& segment = *it;
size_t toProduce = (std::min)(segment.writeAvailable(), remaining);
SegmentData data = segment.writeBuffer().slice(0, toProduce);
#ifdef WINDOWS
while (data.length() > 0) {
iovec wsabuf;
wsabuf.iov_base = (void *)data.start();
wsabuf.iov_len = iovLength(data.length());
result.push_back(wsabuf);
data = data.slice(wsabuf.iov_len);
}
#else
iovec iov;
iov.iov_base = (void *)data.start();
iov.iov_len = data.length();
result.push_back(iov);
#endif
remaining -= toProduce;
++it;
}
MORDOR_ASSERT(remaining == 0);
invariant();
return result;
}
void
Buffer::Segment::produce(size_t length)
{
MORDOR_ASSERT(length <= writeAvailable());
m_writeIndex += length;
invariant();
}
int Buffer::pushBytesFromStream(std::basic_istream<char>& istr, int cnt)
{
if (writeAvailable() < cnt)
cnt = writeAvailable();
istr.read((char*)_tail, cnt);
if (istr.eof())
{
cnt = istr.gcount();
}
else if (istr.fail())
{
return -1;
}
_tail += cnt;
return cnt;
}
iovec
Buffer::writeBuffer(size_t length, bool coalesce)
{
iovec result;
result.iov_base = NULL;
result.iov_len = 0;
if (length == 0u)
return result;
// Must allocate just the write segment
if (writeAvailable() == 0) {
reserve(length);
MORDOR_ASSERT(m_writeIt != m_segments.end());
MORDOR_ASSERT(m_writeIt->writeAvailable() >= length);
SegmentData data = m_writeIt->writeBuffer().slice(0, length);
result.iov_base = data.start();
result.iov_len = iovLength(data.length());
return result;
}
// Can use an existing write segment
if (writeAvailable() > 0 && m_writeIt->writeAvailable() >= length) {
SegmentData data = m_writeIt->writeBuffer().slice(0, length);
result.iov_base = data.start();
result.iov_len = iovLength(data.length());
return result;
}
// If they don't want us to coalesce, just return as much as we can from
// the first segment
if (!coalesce) {
SegmentData data = m_writeIt->writeBuffer();
result.iov_base = data.start();
result.iov_len = iovLength(data.length());
return result;
}
// Existing bufs are insufficient... remove them and reserve anew
compact();
reserve(length);
MORDOR_ASSERT(m_writeIt != m_segments.end());
MORDOR_ASSERT(m_writeIt->writeAvailable() >= length);
SegmentData data = m_writeIt->writeBuffer().slice(0, length);
result.iov_base = data.start();
result.iov_len = iovLength(data.length());
return result;
}
void
Buffer::reserve(size_t length)
{
if (writeAvailable() < length) {
// over-reserve to avoid fragmentation
Segment newSegment(length * 2 - writeAvailable());
if (readAvailable() == 0) {
// put the new buffer at the front if possible to avoid
// fragmentation
m_segments.push_front(newSegment);
m_writeIt = m_segments.begin();
} else {
m_segments.push_back(newSegment);
if (m_writeAvailable == 0) {
m_writeIt = m_segments.end();
--m_writeIt;
}
}
m_writeAvailable += newSegment.length();
invariant();
}
}
void
Buffer::compact()
{
invariant();
if (m_writeIt != m_segments.end()) {
if (m_writeIt->readAvailable() > 0) {
Segment newSegment = Segment(m_writeIt->readBuffer());
m_segments.insert(m_writeIt, newSegment);
}
m_writeIt = m_segments.erase(m_writeIt, m_segments.end());
m_writeAvailable = 0;
}
MORDOR_ASSERT(writeAvailable() == 0);
}
void
Buffer::produce(size_t length)
{
MORDOR_ASSERT(length <= writeAvailable());
m_readAvailable += length;
m_writeAvailable -= length;
while (length > 0) {
Segment &segment = *m_writeIt;
size_t toProduce = (std::min)(segment.writeAvailable(), length);
segment.produce(toProduce);
length -= toProduce;
if (segment.writeAvailable() == 0)
++m_writeIt;
}
MORDOR_ASSERT(length == 0);
invariant();
}
